+/*
+ * Sync metadata meaning request them to the session daemon and snapshot to the
+ * metadata thread can consumer them.
+ *
+ * Metadata stream lock MUST be acquired.
+ *
+ * Return 0 if new metadatda is available, EAGAIN if the metadata stream
+ * is empty or a negative value on error.
+ */
+int lttng_kconsumer_sync_metadata(struct lttng_consumer_stream *metadata)
+{
+ int ret;
+
+ assert(metadata);
+
+ ret = kernctl_buffer_flush(metadata->wait_fd);
+ if (ret < 0) {
+ ERR("Failed to flush kernel stream");
+ goto end;
+ }
+
+ ret = kernctl_snapshot(metadata->wait_fd);
+ if (ret < 0) {
+ if (errno != EAGAIN) {
+ ERR("Sync metadata, taking kernel snapshot failed.");
+ goto end;
+ }
+ DBG("Sync metadata, no new kernel metadata");
+ /* No new metadata, exit. */
+ ret = ENODATA;
+ goto end;
+ }
+
+end:
+ return ret;
+}